Magnetic trapping of ultracold neutrons

Three-dimensional magnetic confinement of neutrons is reported. Neutrons are loaded into an Ioffe-type superconducting magnetic trap through inelastic scattering of cold neutrons with 4He. Scattered neutrons with sufficiently low energy and in the appropriate spin state are confined by the magnetic field until they decay. The electron resulting from neutron decay produces scintillations in the liquid helium bath that results in a pulse of extreme ultraviolet light. This light is frequency downconverted to the visible and detected. Results are presented in which 500 +/- 155 neutrons are magnetically trapped in each loading cycle, consistent with theoretical predictions. The lifetime of the observed signal, 660 s +290/-170 s, is consistent with the neutron beta-decay lifetime.Comment: 17 pages, 18 figures, accepted for publication in Physical Review

Respiratory Syntitial virus persistence in the lungs correlates with airway hyperreactivity in the mouse model

Background. Previous studies in mice showed that respiratory syncytial virus (RSV) infection was associated with RSVRNApersistence. This study was designed to characterize the significance of RSVRNApersistence and its relation to RSV-induced chronic airway disease. Methods. Mice were inoculated with live RSV, UV light-treated RSV, heat-inactivated RSV, or medium. Bronchoalveolar lavage fluid samples were obtained and lung specimens were harvested on days 1, 5, and 42 after inoculation to assess lung inflammation, lung mRNA expression of interleukin (IL)-4, IL-5, IL-15, and interferon (IFN)-\u3b3; RSV loads were assessed by culture and real-time polymerase chain reaction (PCR) and correlated with pulmonary function. Results. During the acute phase of infection, RSV loads as indicated by culture and PCR were significantly higher in mice inoculated with live RSV. On day 42, RSV RNA remained detectable only in mice inoculated with live or UV light-treated RSV. Lung inflammation, IFN-\u3b3:IL-4 mRNA expression ratios, airway obstruction (AO), and airway hyperreactivity (AHR) were significantly increased in mice inoculated with live RSV. AO on day 5 and AHR on day 42 were significantly correlated with RSV RNA copy number in lung samples. Conclusions. Infection with live RSV induced acute and chronic airway disease that was associated with a predominantly Th-1 immune response and RSV RNA persistence that significantly correlated with pulmonary function abnormalities

Matrix metalloproteases and epithelial-to-mesenchymal transition: Implications for carcinoma metastasis

The epithelial to mesenchymal transition (EMT) is characterized by the loss of epithelial characteristics and the gain of mesenchymal attributes in epithelial cells. It has been associated with physiological and pathological processes requiring epithelial cell migration and invasion. Initially, EMT was observed in embryological and adult development with many well characterized examples including the conversions of epiblast to primary mesenchyme (gastrulation), somite to sderotome, somite to dermis, myotome to migratory myoblast, dorsal neural tube to neural crest, placodal ectoderm to cranial ganglion precursor, intermediate mesoderm to nephric mesenchyme, lateral mesoderm to connective/muscular tissue, endocardium to cardiac cushion mesenchyme and trophectoderm invasion.[1],[2] In addition, evidence is mounting to support an important role of EMT pathways in the progression of carcinoma to metastasis providing epithelial tumour cells with the ability to migrate, invade the surrounding stroma and disseminate in secondary organs.[3]–[5